Last year’s tally for West Nile virus illnesses in the United States was the highest since 2003.

Of 5780 cases of arboviral disease reported in 2012, West Nile virus infection accounted for 5674, or 98% of the total, researchers reported in the Morbidity and Mortality Weekly Report. The high number of cases, including the first human case ever reported in Maine, was attributed to a large, multistate outbreak. The national toll from West Nile virus infections included 2873 cases of neuroinvasive disease, 3491 hospitalizations, and 286 deaths. The median age of those who died was 77 years.